Apparatus for folding a running web of flexible material



,July 21, 1959 s. E. NILSSON 2,895,731

APPARATUS FOR FOLDING A RUNNING WEB OF FLEXIBLE MATERIAL Filed April 8, 1957 2 Sheets-Sheet 1 Fig.1

HVVE/VTUR STEN E/NAR N/LssoN.

July 21, 1959 I s. E. NILSSON 2;895,731

APPARATUS FOR FOLDING A RUNNING was OF FLEXIBLE MATERIAL Filed April 8, 1957 2 Sheets-Sheet 2 B STEN .E/NAR N/IL-SSON ,J '5 III United States Patent APPARATUS FOR FOLDING A RUNNING WEB OF FLEXIBLE MATERIAL Sten Einar Nilsson, Lund,-Sweden Application April8, 1957, Serial No. 651,327

Claims priority,applicationSweden April 17, 1956 4 Claims. (Cl. 270-86) The present invention relates to an improved apparatus for folding an edge zone of a running flexible material web which except the edge zone at least along that portion of its length corresponding to the folding operation defines a surface substantially perpendicular to an imagined plane.

Inter alia within the packaging industry, it is often desirable simultaneously with winding off a Web, e.g. of paper, from a supply roll to fold a web edge zone to make it form a predetermined angle with the rest of the web or double over same.

Previously known apparatus for such folding of a running web edge zone a predetermined angle are of a relatively complicated nature and require correspondingly complex expedients.

In contradistinction thereto the apparatus in accordance to the invention is particularly simple and easily realizable. Thus, it is substantially characterized in that first the web is continuously creased or scored along a line defining the edge zone in question and in connection thereto is guided in such a manner as during the whole of the folding operation constantly to maintain said crease or score line in one and the same plane parallel to said imagined plane, whereupon the edge zone thus defined for folding about said crease line is acted upon by .anexternal force component perpendicular to the crease line in the corresponding point and parallel to the crease line plane, and finally the web for completing the edge zone folding is successively bent so as to give its direction of movement a component of opposite direction in relation to said external force component.

Advantageously said apparatus lends itself to application in connection with carrying out a method for producing packages impermeable to liquids having low surface tension from flexible multiply webs having one layer of fibrous nature and one liquid repellent homogeneous outer layer through bending the web into tube form, said liquid repellent homogeneous outer layer facing inwardly, joining the longitudinal web edge zones to form a longitudinal joint and sealing the tube ends to enclose a liquid in the package thus produced. In accordance With said method at least one longitudinal web edge zone is doubled over the web outside corresponding to the outside of the tube being formed through folding about its inner boundary line parallel to the corresponding web edge, whereupon the longitudinal web edge zones are joined to form a longitudinal joint, their faces having the liquid repellent homogeneous layer facing each other.

More particularly, the improved edge folding apparatus comprises a guiding means for guiding the web as well as for creasing or scoring same along a line, and a bending means for initiating the edge zone folding about the crease line as well as for completing this folding through a successive bending of the web.

The invention will hereinafter be described more fully with reference to the accompanying drawing on which Fig. 1 is a front view of an apparatus for carrying out perpendicular to the corresponding substantially plane por- 2,895,731 Patented July 21,

the method according to the invention, Fig. 2 being a side view of said apparatus.

The folding apparatus shown on the drawing comprises an automatic web guiding device constituted of a L-shaped bell crank 1, 2 pivotable about a pivot 4 in a forked end 5 of a supporting arm 6 the other end of which is fixed to a machine frame 7, said pivot 4 being substantially tion of a running material web 3 having a straight side edge. The shorter branch 1 of the bell crank 1, 2 carries two guide rollers 8 and'9 which in co-operation engage either face of the web 3 under a substantially constant pressure and are freely rotatable each about its own of two shafts 10 and 11 parallel to each other and to the web 3 and lying in a plane perpendicular thereto. The longer bell crank branch 2 extending from the pivot 4 in a direction opposite to the direction of movement of the web 3 carries at its free end a feeler 12 having a curved operating surface 13 adapted constantly to engage the corresponding edge 14 of the web 3 so as to cause the bell crank 1;, 2 to assume a stable angular position about the pivot 4 wherein the undeformed web edge 14 is in a fixed plane parallel to the pivot 4 and to the direction of longitudinal movement of the web 3. Upon any tendency to transverse displacement of the web 3 in either direction the bell crank 1, 2 will be pivoted out of its stable angular position, whereby the angle between the roller shafts 10 and 11 and the direction of longitudinal movement of the web will be changed, which change the guide rollers 8 and 9 will tend to oppose in order to restore the stable balance position of the bell crank.

One guide roller 8 is on its cylinder surface provided with a coaxial annular ridge 15, while the other guide roller 9 may be provided with a corresponding'groove. When the guide rollers '8 and 9 rotatingly engage the running web 3 the face thereof corresponding to the ridged guide roller '8 will be provided with an embossed creasing or scoring line 16 which because of the transverse guiding of :the web 3 will define an edge zone 17 of uniform width and at least along the portion of the web corresponding'to the folding operation will be located in a plane parallel to the direction of longitudinal movement of the web 3 and the pivot 4.

After the guide rollers 8 and 9 in the direction of movement of the web there is located a cylindrical pulley roll 18 rotatable about a shaft 19 fixed to the frame 7 and of such position that the web with the exception of the edge zone 17 during the folding operation will define a surface perpendicular to an imagined plane.

At its end corresponding to the edge zone 17 the pulley roll 18 is provided with an end flange 20 of greater diameter than the rest of the roll 18. The pulley roll 18 is positioned in such a manner along the shaft 19 that the crease line 16 will constantly be located in the plane containing the intersection of the cylindrical surface of the pulley roll 18 and the inner face of the end wall flange 20. The end wall flange 20 is adapted in its rotation corresponding to the travelling direction of the web 3 frictionally to engage the web edge zone 17 to cause this to initiate a folding movement about the crease line 16. As shown in Fig. 1, the inner face of the flange 20 applies a continuous moment to the edge or margin zone 17 so as to initially fold the same gradually about the crease or score line 16 towards and somewhat beyond a plane therethrough perpendicular to the remaining width of the web 3.

The folding of the web edge zone 17 about the crease line is completed to the extent intended in the engagement of the web 3 and the cylindrical surface of the pulley roll 18, the degree in which the web 3 engagingly encircles the pulley roll 18 determining the angle the web edge zone 17 will form with the rest of the web 3 after completed folding. On the drawing there is assumed that the web edge zone 17 is completely doubled over the web 3. l

The end wall flange 20 is given such a profile fitted to the folding result intended that the inner face thereof will approximately conform in shape to the corresponding portion of the web edge zone 17 being folded.

Between the pulley roll 18 and the guide rollers 8 and 9 there is a rod shaped counter force member 21 which is fixed to but may be adjustably attached to the frame 7. The free, rounded off end of member 21 is adapted to engage the side of the web 3 facing away from the pulley roll 18 near to the crease line 16 on the opposite side thereof in relation to the edge zone 17 as well as near to the end wall flange 20. When the edge zone 17 is folded by the end wall flange 20 the presence of the member 21 will oppose the tendency of the web 3 towards a local deformation into convex shape as viewed from the web side facing away from the pulley roll 18 that should complicate the folding operation. Advantageously the member 21 is caused locally to deform the web 3 into a concave shape consistent with the folding and with the material of the web 3.

By means of the pulley roll 18 there is achieved that the tensile stresses of the web material caused by the bending of the web 3 over said pulley roll 18 are utilized for completion and fixation of the folding.

For setting a suitable balance position of the bell crank 1, 2 the feeler 12 is adjustable in relation to the longitudinal extension of the longer branch 2 by means of a set screw 23. From the longer branch 2 there also extends a plate 22 substantially parallel to the roller shafts 10 and 11 and having a V-shaped slot 24 adapted to accommodate the Web edge 14 and to facilitate the entering thereof between the guide rollers 8 and 9. Preferably the guide rollers 8 and 9 are resiliently arranged in relation to each other, the spring force acting on them advantageously being adjustable for adapting the contact pressure of the rollers 8 and 9 to material webs of various natures.

I claim:

1. An apparatus for folding a longitudinal margin zone of a running flexible web, comprising means for continuously scoring the web along a line defining said margin zone, means for continuously applying a moment to said margin zone initially to fold the same gradually about said score line towards and somewhat beyond a plane therethrough perpendicular to the remaining width of said Web, and means subsequently for continuously and gradually folding said margin zone about said score line towards the adjacent web face and into a final folding position desired, said final folding means comprising a pulley roller engagingly enveloped by one web face along an arc of circle corresponding to the final degree of folding desired, said moment-applying means comprising the inner face of an end wall flange of said pulley roller, said end wall flange being of a diameter greater than that of the pulley roller proper, and said scoring means maintaining said score line substantially in a plane perpendicular to the axis of said pulley roller and passing through the intersection of the cylindrical surface thereof and said inner face of said end wall flange.

2. An apparatus as claimed in claim 1, wherein said scoring means comprises a pair of co-operating rollers engaging opposite faces of the web, and a feeler engaging the adjacent web edge for varying the angle between the axes of said co-operating rollers and the travel direction of the web in response to transverse variations of said adjacent web edge, said co-operating rollers being provided with means for producing said score line.

3. An apparatus as defined in claim 2 wherein said pair of co-operating rollers are mounted for rotation on one arm of a pivotally mounted bell crank lever and said feeler is mounted on the other arm of said bell crank lever.

4. An apparatus as claimed in claim 1 further comprising means engaging the web length intermediate said scoring means and said pulley roller in the vicinity of said score line and on the face opposite to the web face engaging said pulley roller, thereby to oppose to a local displacement of said score line in said plane caused by the folding of said margin zone.

References Cited in the file of this patent UNITED STATES PATENTS 2,521,187 Robinson Sept. 5, 1950 2,655,082 Amyx Oct. 13, 1953 2,799,211 Zerlin July 16, 1957 

